/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/* vim: set ts=8 sts=2 et sw=2 tw=80: */

/* This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/* class that a parent frame uses to reflow a block frame */

#ifndef nsBlockReflowContext_h___

#define nsBlockReflowContext_h___

#include "nsIFrame.h"

#include "mozilla/ReflowOutput.h"

class nsLineBox;

class nsPresContext;

namespace mozilla {

class BlockReflowInput;

} // namespace mozilla

/**

 * An encapsulation of the state and algorithm for reflowing block frames.

 */

class nsBlockReflowContext {

  using BlockReflowInput = mozilla::BlockReflowInput;

  using ReflowInput = mozilla::ReflowInput;

  using ReflowOutput = mozilla::ReflowOutput;

public:

  nsBlockReflowContext(nsPresContext* aPresContext,

                       const ReflowInput& aParentRI);

  ~nsBlockReflowContext() { }

  void ReflowBlock(const mozilla::LogicalRect& aSpace,

                   bool                        aApplyBStartMargin,

                   nsCollapsingMargin&         aPrevMargin,

                   nscoord                     aClearance,

                   bool                        aIsAdjacentWithBStart,

                   nsLineBox*                  aLine,

                   ReflowInput&          aReflowInput,

                   nsReflowStatus&             aReflowStatus,

                   BlockReflowInput&         aState);

  bool PlaceBlock(const ReflowInput& aReflowInput,

                  bool aForceFit,

                  nsLineBox* aLine,

                  nsCollapsingMargin& aBEndMarginResult /* out */,

                  nsOverflowAreas& aOverflowAreas,

                  const nsReflowStatus& aReflowStatus);

  nsCollapsingMargin& GetCarriedOutBEndMargin() {

    return mMetrics.mCarriedOutBEndMargin;

  }

  const ReflowOutput& GetMetrics() const {

    return mMetrics;

  }

  /**

   * Computes the collapsed block-start margin (in the context's parent's

   * writing mode) for a block whose reflow state is in aRI.

   * The computed margin is added into aMargin, whose writing mode is the

   * parent's mode as found in mMetrics.GetWritingMode(); note this may not be

   * the block's own writing mode as found in aRI.

   * If aClearanceFrame is null then this is the first optimistic pass which

   * shall assume that no frames have clearance, and we clear the HasClearance

   * on all frames encountered.

   * If non-null, this is the second pass and the caller has decided

   * aClearanceFrame needs clearance (and we will therefore stop collapsing

   * there); also, this function is responsible for marking it with

   * SetHasClearance.

   * If in the optimistic pass any frame is encountered that might possibly

   * need clearance (i.e., if we really needed the optimism assumption) then

   * we set aMayNeedRetry to true.

   * We return true if we changed the clearance state of any line and marked it

   * dirty.

   */

  bool ComputeCollapsedBStartMargin(const ReflowInput& aRI,

                                    nsCollapsingMargin* aMargin,

                                    nsIFrame* aClearanceFrame,

                                    bool* aMayNeedRetry,

                                    bool* aIsEmpty = nullptr);

protected:

  nsPresContext* mPresContext;

  const ReflowInput& mOuterReflowInput;

  nsIFrame* mFrame;

  mozilla::LogicalRect mSpace;

  nscoord mICoord, mBCoord;

  nsSize mContainerSize;

  mozilla::WritingMode mWritingMode;

  ReflowOutput mMetrics;

  nsCollapsingMargin mBStartMargin;

};

#endif /* nsBlockReflowContext_h___ */